A novel approach of utilizing quaternized chitosan as a catalyst for the eco-friendly cycloaddition of epoxides with CO2

A novel attempt of using quaternized chitosan (QCHT) as a catalyst for the cycloaddition reaction of allyl glycidyl ether (AGE) and CO2 under solvent-free conditions has been made. The surface quaternization of CHT has been characterized by means of various physicochemical methods, such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and elemental analysis. The effects of reaction parameters like catalyst amount, reaction time, reaction temperature, and CO2 pressure have been investigated. The catalyst system was recyclable and was reused. It has been demonstrated that the inherently present hydroxyl group in the catalyst had a synergistic effect with halide anions, and a high yield of cyclic carbonates and excellent selectivity could be obtained under optimum conditions. These results reveal that QCHT is an efficient and environmentally friendly catalyst for the cycloaddition reaction.